Variable high pressure transition tube set point adapter

ABSTRACT

An apparatus, method, and system for inserting and securing a high pressure transition tube of a fluid transfer tool assembly into a positive position whereby the seal element is packed off in the wellhead set point. Once attached the transition tube is pushed to contact the bit guide, secondary seal or bore machine prep. A lower nose compression seal is seated against transition tube and compressed using an energizer seal to isolate and protect lower pressure wellhead and well control equipment from the higher rated frack pressures or pushing the transition tube and lower nose isolation compression seal to contact the bit guide, secondary seal or bore prep. Pressure is applied to push a seal against the lower and upper compression ring locking them in place preventing movement to form a compression seal and isolating the high pressure passing through the transition tube protecting the wellhead assembly and well control equipment.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 61/886,192 filed Oct. 3, 2013, assigned to Assignee hereof, and thespecification of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)

The presently claimed invention relates to oil and gas drilling systems,and more particularly to systems for insertion tools, for inserting andsecuring a high-pressure transition tube of a fluid/gas, and a transfertool apparatus assembly into a positive position in which the sealelement is packed off in the wellhead set point. The claimed inventionis for the process of fracking, a method developed and used to crackopen the formation at high pressures and to help the stimulations of oiland gas well production, and a tool, apparatus, and a configurationequipment and method for protecting frack containment and controlequipment and wellhead from exposure to pressures higher than thepre-design operating range and from the abrasive and or corrosive fluidsduring well fracturing and pumping procedures.

2. Background Art

Wells require some form of stimulation called fracking to stimulateproduction and make or keep them productive. The fracking of oil and gaswells formations to stimulate production requires that high pressurepumping equipment be used to inject fluids, chemicals, and sands at highpressures. The frack fluids are generally corrosive and abrasive becauseof acids and abrasives used to open cracks in the formations withspecial sand.

New technology and methods as well as safety and environmentalregulations that are being adopted industry wide cannot be accomplishedwith the lower pressure frack containment equipment, Blowout Preventers(BOPs) or through a valve attached to the wellhead. The practice offracking or pumping through BOPs equipment, valves or wellheads atpressures higher that the pre-engineered design pressure rating has beendetermined to be unsafe and is no longer Standard Operating Practice(SOP).

This method was adopted because it was the only way to have full accessto a well casing bore with down-hole tools during the well fracking orservicing. The industry's known methods and technologies indicate thatnew methods must be developed to acquire full bore access to well boreat much higher pressures. Full bore access to the casing permits use ofdown-hole tools that are often required during a frack stimulationtreatment without having to remove tools or equipment betweenmulti-stage frack stimulation, as was required with older styleconventional wellhead isolation tools such as disclosed in U.S. Pat. No.4,867,243, entitled WELLHEAD ISOLATION TOOL AND SETTING AND METHOD OFUSING SAME.

An apparatus for providing full access to the casing while permittingstimulation treatments at extreme pressures that approach a burstpressure rating of the casing is described in U.S. Pat. No. 6,289,993,entitled BLOWOUT PREVENTER PROTECTION AND SETTING TOOL.

Another prior art reference describes an apparatus and method ofisolating a well tree located on an oil or gas well from the effects ofhigh pressure or corrosion caused by stimulation of a well is describedin U.S. Pat. No. 4,867,243 entitled WELLHEAD ISOLATION TOOL AND SETTINGTOOL AND METHOD OF USING SAME. This reference describes an apparatus topermit the injection of fluids, gases, solid particles, or mixturesthrough a well tree while protecting the well tree during wellstimulation treatments. The apparatus includes a single hydrauliccylinder supported in an axial alignment over a well tree by at leasttwo elongated support rods. The hydraulic cylinder support rods areconnected between a base plate and a hydraulic cylinder support platefor supporting the hydraulic cylinder above the well tree at a distanceapproximately equal to the height of the production tree.

This device permits the insertion of a single length of high pressuretubing through any well tree regardless of its height. Once thehigh-pressure tubing is seated in a well tubing or casing, the hydrauliccylinder, hydraulic cylinder plate, and support rods are removed toprovide 360° access to a high-pressure valve attached to the top of thehigh-pressure tubing. The bottom end of the high-pressure tubing has apackoff nipple assembly that is inserted into the production tubing orcasing and seals against the inner wall. Thus, the extent to which thehigh pressure tubing extends into the production tubing or casing isunimportant so long as the packoff nipple assembly is sealed against theinner wall. Consequently, variations in the length of the productiontree are of no consequence and a lockdown mechanism with a short reachis adequate. Therefore, there exists a need for a mechanical lockdownmechanism that provides a broad range of adjustment to permit packoffwith a fixed packoff surface in a wellhead.

SUMMARY OF THE INVENTION

The presently claimed invention overcomes the shortcomings of the priorart by providing a locking mechanism, described as a variable adjusterlocking sleeve, which houses and forms a barrier around a high pressuretransition tube. The variable adjusting locking sleeve is capable of upand down vertical movement while simultaneously providing a pressurizedbarrier around the variable high pressure transition tube and in theunibody master housing with test ports to verify seal integrity.Additionally, the presently claimed invention prevents exposure of thebarrel, which creates safety and environmental hazards if a breach orinternal wash or damage occurs.

When the mechanical locking mechanisms are attached or applied, thevariable adjuster sleeve houses the high pressure variable transitiontube and assembly to achieve a double barrier pressure seal and a doubleretention locking ring, which are not available in prior art. Theclaimed invention greatly improves the art of wellhead equipmentisolation tools and the protection from high pressures, corrosivechemicals, and abrasive sand to-well control equipment, blowoutpreventers (BOPs), flow control valves, flow spools other equipmentknown in the industry by sealing and protecting from high well pumpfrack stimulation pressures, and to overcome the design shortcomings,safety and environmental concerns of the prior art.

It is the intention of the presently claimed invention to provide anisolation seal barrier for protection of well control equipment and safeoperation for personnel and environmental protection while stillaccessing high-pressure fracking technology during the well stimulationprocess and treatment.

It is also a further object of the presently claimed invention toprovide an isolation seal barrier for protection from high pressures,corrosive chemicals, and abrasive sand-to-well control equipment such asblowout preventers (BOPs), flow control valves that are secured andlocked into position by a mechanical locking mechanism capable ofsealing and providing a pressure protection barrier. It is a furtherobject of the present invention to provide a safety and environmentalprotection to personnel and environment through engineering design.

In accordance with one aspect of the presently claimed invention, thereis provided, an apparatus for protecting well control equipment fromexposure to fluid pressures, abrasives, and corrosive fluids used inwell treatment to stimulate production. The apparatus comprises a highpressure transition tube adapted to be inserted down through the wellcontrol equipment to an operative position. The high pressure transitiontube has a top end and a bottom end, the high pressure transition tubebottom end including prep for a hollow nose bullet sealing assembly forsealing engagement in the wellhead casing seal with a top metalenergizer ring seated on top of the casing seal bit guide. The assemblyis compressed when weight or force is introduced compressing the sealbetween the steel energizer rings, thus, forcing an elastomer seal tocompress and expand outward against the wall of the wellhead bore, thus,eliminating the need to have a controlled tolerance or pre-engineeredmeasurements or dimensions such as are needed with o-ring style seals.

When the high pressure transition tube and hollow nose bullet seal arein the operative position, a mechanical lockdown mechanism detachablysecures the high pressure transition tube to the well control equipment.The lockdown mechanism being adapted to ensure that the hollow nose sealassembly sealing body is securely seated against the top of the casingand in the wellhead secondary seal when the high pressure transitiontube is in the operative position. The mechanical lockdown mechanismpreferably includes a variable adjuster locking sleeve, high pressurevariable transition tube, hollow nose seal assembly, and a unibodymaster housing that is manufactured to universal API 6A standards. Thevariable high pressure transition tube mechanical lockdown mechanism ismounted to a top of the well control equipment, and the variable tubehousing adapter has a centered passage port to permit the installationand removal of the variable tube. The passage port provides housing forthe high pressure variable tube sleeve that has machined thread forengaging the high pressure variable tube and a high pressure adapter orwell control valve. The high pressure adapter or well control valve isadapted to secure and retain the high pressure tube and high pressurevariable seal assembly in the operative position. The variabletransition tube spiral thread length is adequate to ensure positiveretention and safe operation at well stimulation fluid pressures such as10,000 to 15,000 Pounds per Square Inch (PSI).

The high pressure variable pass-through tube has at least one externaland one internal spiral thread, and one on the high pressure variabletransition tube adjuster adapter. The high pressure variable transitiontube adjuster adapter has a length adequate to provide a significantrange of adjustment, preferably at least about 5″ (12.5 cm), tocompensate for variations in a distance between a top of the closingequipment (valve and/or BOP), the secondary seal assembly, and bore wallof the tubing head assembly, where the high pressure variable sealassembly inserts into the casing seal prep profile and packs off. Themandrel may be cycled in and passed through the well control equipmentusing any type of mechanical push/pull mechanism for the insertion ofhigh pressure variable tube assembly or wellhead saver. Once inserted,the high pressure variable tube assembly is securely locked in itsoperative position by adjusting the variable adjustment pressure adapteruntil it contacts the frack adapter head retainer mechanical lockingmechanism, and is locked in the optimum position.

The presently claimed invention provides a method for protecting thetubing head wellhead assembly, well control equipment, and otherequipment from exposure to abrasive, and corrosive fluids and pressuresabove the intended manufactured design during a well frack andstimulation process. The tool assembly comprises a variable highpressure transition tube, a unibody high pressure transition valve orfrack valve adapter head designed to be inserted down through the wellcontrol equipment and connected to a top end variable adjuster lockingsleeve adapter. The unibody high pressure transition valve or valveadapter head is adapted to and connected to the variable high pressuretransition tube and protrudes above the unibody master housing, wellcontrol equipment, and the variable high pressure transition hollow nosebull seal. The variable high pressure transition hollow nose bull sealassembly end includes a wellhead through bore wall elastomer compressionseal and at least one sliding sleeve energizer ring when inserted forsealing with a secondary back up compression energized seal. Thesecondary compression energized seal compresses with force against thewellhead through bore wall when the hollow nose bullet seal assembly andvariable high pressure transition tube are locked into position.

A mechanical push/pull insertion mechanism is used for inserting thevariable high pressure tube into and removes the variable high pressuretube in and out of the well control equipment. The mechanical push/pullinsertion mechanism is supported by at least two elongated variableshank rods attached to the unibody master housing shank rod plate andintegrated API flange. The unibody master housing API flange is sized tomate to the well control equipment for supporting the mechanicalpush/pull insertion mechanism in vertical and axial position set abovethe well control equipment and high pressure transition tube unibodymaster housing and shank rod plate. The shank rods and the mechanicalpush/pull mechanism are removable once the unibody pressure transitionvalve and variable high pressure transition tube and hollow nose bulletseal assembly are inserted through the well control equipment.

A primary advantage of the presently claimed invention is the use of avariable adjuster locking sleeve adapter. The variable adjuster lockingsleeve adapter locking mechanism has several advantages that make itsuperior to the prior art. One primary advantage is the double barrierdesign that encapsulates and houses the variable high pressuretransition tube, whereby the variable adjuster locking sleeve adapterallows the high pressure variable tube to pass and slide through, and upand down while maintaining a back pressure seal during the in and outinstallation process.

Another advantage of the presently claimed invention is that the highpressure transition tube is completely housed and sealed by the variableadjuster locking assembly. The variable adjuster locking sleeve adapteris designed with internal and external seals that can be externallyhydraulically tested for seal integrity.

Another advantage not available in prior art is that the variableadjuster locking sleeve adapter is also fitted with metal to metal ringseal, that once locked down into place forms a double barrier seal. Thisis optimal because even if the high pressure variable tube is damaged,breached, or washed through, it is contained within the outer shell ofthe variable adjuster assembly with seals the contain pressureinternally to safely protect personnel and the environment.

Other advantages of the presently claimed invention are quick connectingdouble retention for rods and low profile for easy access to wellcontrol equipment. In addition, the security provided by a mechanicaldouble lockdown mechanism is independent and provides a back-up lockfurther securing to ensure retention of the high pressure transitiontube that eliminates safety and environmental concerns.

Other advantages include the ability to pressure test high pressuretransition tube seals for integrity, and a removable shank rod plate andadjustable shank rods are configured to fit different variations ofequipment lengths, which reduces cost and offers versatility.

Furthermore, the separable shank plate's adjustable rods, the quickconnect guides, and removable insertion tool reduces manufacturing andmaintenance costs of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a partof the specification, illustrate several embodiments of the presentlyclaimed invention, and together with the description, serve to explainthe principles of the presently claimed invention. The drawings are onlyfor the purpose of illustrating a preferred embodiment of the claimedinvention and are not to be construed as limiting the presently claimedinvention.

FIG. 1-1 shows the top half of a cross-sectional exploded view of thepreferred unibody master housing assembly with variable adjuster lockingsleeve adapter assembly viewed in various positions of verticalinstallation positions. FIG. 1-1 also shows the variable high pressuretransition tube in an exploded view inserted into the pressuretransition control valve. It features the external test ports fortesting pressure transition tube seals and locking mechanism metal seal,shank plate and locking ring installed in the master housing, backupvariable adjuster locking sleeve adapter retainer ring, with internaland external tube seals with upper and lower test ports to test sealintegrity of unibody master housing and pressure transition tube.

FIG. 1-2 is the bottom half of the cross-sectional exploded view of thepreferred high pressure variable tube assembly with the hollow bulletnose seal assembly installed in the variable tube and inserted into thewellhead casing secondary seal. FIG. 1-2 illustrates the metal energizercompression ring seated to the top of the secondary seal bit guide, theelastomer compression seal protruding or pushing outwards as force isapplied to compress against the bore wall of the wellhead and twodifferent forms of seals working simultaneously.

FIG. 2 is a cross-sectional view of the variable adjuster lockingassembly and unibody master housing assembly with variable adjusterlocking sleeve assembly disengaged as shown in FIGS. 1-1 and 1-2. Italso illustrates the variable high pressure transition extracting outand away from the disengaged variable adjuster locking sleeve andtraveling up in a vertical path away from the unibody master housing andtraveling through the variable adjuster locking sleeve adapter andseals. FIG. 2 also illustrates how the secondary locking ring worksindependent of the primary locking assembly.

FIG. 3 is a front view of unibody master housing assembly cross sectionwith high-pressure variable transition tube and quick connect shank rodconnection assembly mounted to the shank rod plate with shank rodinserted and securely locked into position with a safety back up locknut installed.

FIG. 4 is an alternate flanged frack valve adapter embodiment to theunibody pressure transition control valve adapter and locking clampmechanism used in the high pressure transition tube well controlequipment protector.

FIG. 5-1 is a front view of the variable high pressure transition toolassembly mounted on well control equipment with the upper and lowershank rod plate assemblies and ram assembly mounted to the shank rodplate with variable adjustable shank rods.

FIG. 5-2 is a partial cross-sectional view of a variable high pressuretransition tube and an embodiment of seal assembly inserted and attachedto a variable high pressure transition tube for sealing against an innerwall of well control equipment.

FIG. 6 is a partial cross-sectional view of an alternate preferredembodiment of an annular sealing body for sealing against the innerwall. It is inserted into a preinstalled casing sealing assembly that isinserted and installed to the casing and mounted and secured in the wellcontrol equipment.

FIG. 7 is a partial cross-sectional view of an alternate preferredembodiment of an annular sealing body for sealing against the inner wallof the well control equipment with a metal to metal compression ringthat seats or butts up to the tool guide of the casing seal. It is thencompressed by force, which preloads and energizes the seal or sealsagainst the inner wall of well control equipment to positively provide aseal.

FIG. 8 is an embodiment of an alternate seal of FIG. 5-2 illustrating ametal ring in contact with a casing secondary seal bit guide used toenergize an elastomer or polyurethane seal when pressure is applied andused to compress the seal against the body of the wellhead bore. Thisforce pushes the seal outward against the bore, which does not requirecontrolled tolerances.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Best Modes for Carrying Out theInvention

FIGS. 1-1 and 1-2 show a cross-sectional view of the variable highpressure transition tool for protecting the wellhead control equipment(hereinafter referred to as variable pressure isolation tool) 10.Variable pressure isolation tool 10 includes a unibody master housing12, a shank rod plate 14 that is drilled, tapped, and prepped with boltthreads uniformly positioned around the radius of shank rod plate 14.Shank rod plate bolts 18 are affixed to shank rod plate 14 and to splitlocking ring 16 that are then placed into position on unibody masterhousing 12 by sliding shank rod plate 14 over the top of upper member ofunibody master housing 12. Unibody master housing 12 can also include atleast two or more split retainer rings 20 that include bolt holes aroundthe radius of split locking ring 16 with vertically aligning holes inshank rod plate 14. Split locking rings 16 are inserted into position inunibody master housing locking ring slot groove 22, shank rod plate 14is lifted into position, and the hole aligned with split locking ring12. One or more shank rod plate bolts 18 are inserted into the alignedholes and rotated into retainer ring bolt threads 24 and tightened ortorqued into position. Unibody master housing 12 is machined andconfigured with a tube seal pocket 26, fitted and sized with seal 30interference against the vertical wall of variable tube seal pocket prep26 that will accept one or more tube seals 30. Variable high pressuretransition tube 32 is inserted into and through vertical bore 34 ofunibody master housing 12 and one or more tube seals 30 are inserted andplaced into position around variable high pressure transition tube 32.Packing retainer ring 36 is placed around variable high pressuretransition tube 32 and slid into position until packing retainer ring 36makes contact with retainer ring threads 38, and is then rotated intoposition and locked in place. Variable high pressure transition tube 32is fitted and prepped with male High Pressure (HP) nose seal prep 42. HPnose seal prep 42 is fitted with at least one or more high pressure tubeseals 44 with spiral threads 46 to engage with complementary unibodypressure transition control valve spiral threads 48 and tube bore 50.Tube bore 50 should be large enough to provide full access to the wellbore casing as shown in FIG. 2. Spiral threads 56 are used to engagewith variable high pressure transition tube complementary spiral threads58 and at least one tube seal upper 60 and a lower outer variable tubeseal 62. Unibody pressure transition control valve 52 has a variabletube test port 64 that enables testing from 10,000 to 15,000 PSI on tubeseal upper 44, and lower outer variable tube seals lower 62 for safetyand seal integrity. Unibody pressure transition control valve 52 isprepped with integrated locking clamp preparation 66 flanged or wingedhub (not shown).

Variable high pressure transition isolation tool assembly 32 is alsoadapted with a variable adjuster locking sleeve 70 with spiral variableadjustable threads 28 that are provided externally for adjusting thesleeve up or down 92 into position to mate with the setting position ofa unibody pressure transition control valve 52 and variable highpressure transition tube 32. Variable adjuster locking sleeve 70 isfitted with inner tube seal 100 and outer seal 102 to prevent escape orspill of any pressurized liquids that might be present should seal 78and tube seal 30 be damaged or have hollow nose bullet seal bodyassemblies 94 that are mated with wellhead seal prep 86 leak. Hollownose bullet seal body assembly 94 is fitted with external complementaryspiral threads 56 and internal complimentary threads 58 that have atleast one external elastomer seal 78 and lower energizer ring 80. Lowerenergizer ring 80 is installed by placing it over and sliding the upperexternal threads 56 and lowering it to no go stop 84. Elastomercompression seal 78 and upper energizer ring 82 are installed using thesame steps.

Bullet nose hollow seal assembly 94 is installed into variable highpressure transition tube 32 by rotating complementary threads 56 and 58until hollow nose bullet seal assembly 94 stops rotating and is fullyengaged. When bullet nose hollow seal assembly 94 engages and is setinside wellhead seal prep 86 with lower energizer ring 80, it stops ontop of wellhead seal bit guide 88. Force is applied by means of weightor hydraulic (not shown) to the top of variable high pressure transitiontool 10 which forces upper energizer ring 82 to push against elastomercompression seal 78 and lower energizer ring 80 compressing andpreloading the seal against the wellhead vertical wall. Variableadjuster locking sleeve 70 is usually pre-set to the lowest operationposition of variable adjustment 74 by rotating clockwise or counterclockwise on threads 28 of the variable adjuster tube sleeve and masterhousing thread 29 to match the final optimum setting position of hollownose seal assembly 94 and unibody pressure transition valve 52. Lockingclamp 68 flange or winged connection (not shown) is installed and lockedin the optimum position and clamp bolts 96 are installed and securedinto position.

Variable adjuster locking sleeve 70 is fitted with well-known types ormethods for locking clamping or bolting hub prep 68 and fitted withsteel seal ring prep 40 as a backup pressure containment barrier iflower tube seal 102, 78 fails. Variable adjuster locking sleeve 70 isfitted with an inner seal 100 and outer seal 102 master housing seal 98to prevent exposure and spills should tube seal 102, hollow bullet noseseals 76, or compression seal 78, and master housing seal 30 fail.Variable adjuster locking sleeve 70 also provides a passage bore forvariable high pressure transition tube 32 to pass through and travel upand down or in and out of locking sleeve barrier bore 104. Variableadjuster locking sleeve 70 is fitted with an upper test port 106 to testmaster housing outer locking sleeve seal 98, 102 for seal integrity.Lower test port 108 provides for testing locking sleeve inner seal 100and tube seal 30 for seal integrity.

FIGS. 2 and 3 illustrate the variable high pressure transition tool ofFIGS. 1-1 and 1-2, prior to being mounted above well control equipmentfor a well stimulation treatment. Locking clamp 68 is removed fromvariable adjuster locking sleeve 70 and the lockdown mechanism isdisengaged from unibody high pressure control valve 52 and away fromunibody master housing 118. Rod shank plate 14 and unibody high pressurecontrol valve 52 are connected to the top end of variable high pressuretransition tube 32, which includes any required proper variable highpressure transition tube length section(s) and hollow nose bullet sealpackoff assembly 76 to provide a total length required for a particularwell control equipment or wellhead. Unibody master housing 118 ismounted on the top end of the well control equipment or BOP and thecombination of unibody high pressure control valve 52 with lockdownclamp 68 and variable high pressure transition tube 32, are insertedfrom the top into the well control equipment or BOP using any one ofseveral insertion tools known in the industry. Rod shank plate 14 isfitted with at least two or more rod quick connect assemblies 120 forattaching upper rod shank plate (not shown) and lower rod shank plate14, at least two or more variable rod shanks 122, and at least two ormore rod safety nuts 124 for backup security while inserting or pullingunder pressure.

FIG. 4 illustrates a flanged end valve adapter 128 fitted and preppedwith a female HP nose seal prep 42. Flanged end valve adapter 128 hasspiral threads 46 to engage with variable high pressure transition tubecomplementary spiral threads 48 that have at least one tube seal upper44 and lower outer variable tube 32. Flanged end valve adapter 128 has avariable tube test port 64 that enables testing of 10,000 to 15,000 PSIon tube seal upper 44 and outer variable tube seals lower 62 for safetyand seal integrity. Flanged end valve adapter 128 is prepped withintegrated locking clamp 66 flanged or winged hub (not shown).

The variable high pressure transition tool in FIGS. 5-1 and 5-2illustrates an example of the use of well control equipment and wellheadprotector 10, shown in FIGS. 1-1 and 1-2, using a hydraulic setting toolas described in U.S. Pat. No. 4,867,243, which is incorporated herein byreference. The tool is connected to casing well bore by various casingmethods that are well known in the industry using equipment such as atubing head and tubing spool. Well control equipment are parts anddevices known in the oil and gas industry as wellhead equipment,wellhead components and parts, blow out preventers that are also wellknown in the oil and gas industry and not described in this disclosure.Mounted above the wellhead assembly is the well control equipment thatis used for pressure and fluid flow control during the frackingprocedure and well treatment. The equipment is also used to secure andprevent well fluids from escaping into the atmosphere.

FIG. 5-1 shows variable high pressure transition tool assembly 10mounted to well control equipment 140, unibody high pressure frack valve52 mounted to the top of variable high pressure transition tube 32 tocontrol well pressure and or fluid during the insertion and removal ofvariable high pressure transition tube 32 to prevent well fluids fromescaping to atmosphere. FIG. 5-1 shows the system before variable highpressure transition tool 10 is installed or removed. High pressure valve52 is hydraulically or manually operated or controlled. Hydraulicsetting tool 136 includes a hydraulic cylinder, which is mounted toupper rod shank plate 132. Upper shank rod plate 132 includes passage133 to permit a piston rod for hydraulic cylinder 138 to pass throughupper shank rod plate 14. Upper shank rod plate 132 also includes atleast two attachment points 135 for attachment of variable rod shank 122to shank rod plate 14. Variable rod shank attachment points 135 arepreferably equally spaced from central bore 133 to ensure that thehydraulic cylinder and the piston rod align with unibody pressuretransition control valve 52 to which the hydraulic cylinder attachment(not shown) is mounted. The hydraulic cylinder and variable rod shank122 are respectively attached on their lower shank rod plate 14 ends atcorresponding attachment points on the plate, which is mounted to thetop of well control equipment 140. Lower shank rod plate 14 is supportedby two or more variable rod shanks 122 that are identical in length andare manufactured with course threads described as variable rod shankadjustment threads 130. This permits the upward or downward adjustmentof upper shank rod plate 132 by rotating adjustment nuts 130 toaccommodate variations in lengths or size of equipment. Shank rods 122are attached to the respective attachment points 135 and 120 on uppershank rod plate 132 and lower shank rod plate 14 by means of rod quickconnect assembly 120 comprising of threads or pins and nuts (not shown).

Piston polish rod 133 is attached to the top of the high pressure valve52 by a connector so that mechanical force can be applied by pushing andapplying force to top of unibody wireline valve adapter of well controlto well control equipment 140 protector and the attached high pressurevalve to stroke them in and out of the wellhead. When variable highpressure transition tube 32 is in the operative position shown in FIG.5-2, the bottom end of metal energizer ring assembly 80 is in contactwith a bit guide 88 attached to a top of casing wellhead seal 144. Bitguide 88 covers casing 145 to protect the top end of casing 145 andprovides a seal between casing 145 and wellhead assembly 142 in a mannerwell known in the industry as a secondary seal or wellhead seal 144.

As noted above, variable high pressure transition tube 32 has a variablelength adjustment 74 as illustrated FIG. 1-1, so that hollow nose sealassembly 94, including upper compression seal ring 82, compressionpackoff 78, and lower compression ring 80, have adequate length toensure that the top end of variable adjuster locking sleeve 70 extendsabove the top of unibody master housing 22 with just enough up and downadjustment 74 to rotate and contact with unibody pressure transitionvalve 52. Hollow nose seal assembly 94 is secured by lockdown assemblyclamp 68 described above when packoff assembly 62 is seated against bitguide 94. However, the distance from the top of bit guide 94 and the topof well control equipment 74 may vary to some extent in differentwellheads. This variation cannot be accommodated by a conventionallockdown mechanism such as taught in Applicant's U.S. Pat. No.4,867,243. The presently claimed invention overcomes this shortcoming.

FIG. 6 shows hollow bullet nose seal assembly 94, which comprises fourparts with a unique design that eliminates the need for a retainer ringor no go. The assembly has a lower ring 80, known as the lower energizerring, which seats or contacts the top of wellhead secondary seal 88,known as the wellhead bit guide. Lower energizer ring 80 is installedover bullet nose 94 and thread 58 and slid down to no go stop 84.Compression seal 78 is installed by placing it over the top of thebullet nose seal and then slipped over threads 58 to lower energizerring 80. Upper energizer seal ring is also slipped over the top ofbullet nose 94 and threads 58 until it contacts compression seal 78.Hollow bullet nose seal assembly 94 is now installed to the bottom ofhigh pressure variable transition tube 32, as shown in FIG. 1-2

As shown in FIG. 7, hollow bullet nose seal assembly 94 is comprised offour parts with a unique design that eliminates the need for a retainerring or no go. The assembly has a lower ring 148, known as the lowerenergizer ring that seats or contacts the top of wellhead secondary seal88 (not shown), known as the wellhead bit guide. Lower energizer ring148 is designed with a radius taper positioned to force elastomer seal146 outward to force compression against the outer wall of the wellheadthrough bore as illustrated in FIG. 5-2. The more force that is applied,the tighter the seal is applied to the bore wall ensuring a compressionseal. Compression seal 146 is installed over the nose and thread 58 andslid down to no go stop 84. Compression seal 146 is installed by placingit over the top of the bullet nose seal and slipped over threads 58 tolower energizer ring 148. The radius taper design of compression seal148 matches the radius taper of bottom seal energizer ring 146. Upperenergizer seal ring 82 is also slipped over the top of bullet nose 94and threads 58 until it contacts compression seal 146. Hollow bulletnose seal assembly 94 is now installed to the bottom of high pressurevariable transition tube 32 as shown in FIG. 1-2.

FIG. 8 is an embodiment of an alternate seal as shown FIG. 5-2. FIG. 8illustrates a metal energizer ring in contact with a casing secondaryseal bit guide 88 used to energize an elastomer or polyurethane seal 78when force is applied and used to compress the seal against the body ofthe wellhead bore known in the industry as a through bore. This forcepushes the seal outward against the bore, which does not require acontrolled tolerance or measurement, as in prior art energizer rings.Polyurethane seal 78 is equipped with an outer seal prep 154 and aninner seal prep 152 (not shown), these seals serve to pressure energizethe compression seal 78 without the need for compression. Compression isachieved by inner bore pressure, which forces the compression of seal78. The more pressure, the more compression, and the tighter the seal.Bullet nose seal 94 is inserted and rotated into position by spiralthreads 46 and complimentary threads 48 into high pressure tube whereseals 44 contact high pressure inner wall seal prep. Bore of tube 50 isequal to casing wall 156 which gives the user full access to the wellbore allowing tools to be inserted in and out of the well

Although the claimed invention has been described in detail withparticular reference to these preferred embodiments, other embodimentscan achieve the same results. Variations and modifications of thepresently claimed invention will be obvious to those skilled in the artand it is intended to cover in all such modifications and equivalents.The entire disclosures of all references, applications, patents, andpublications cited above, are hereby incorporated by reference.

What is claimed is:
 1. A variable valve adapter for a high pressurefracking stimulation tool comprising: a high pressure variabletransition tube configured to make contact with a bit guide, secondaryseal or bore machine prep; a variable lower nose isolation compressionseal for seating against the high pressure variable transition tube; anda compression apparatus to compress the high pressure variabletransition tube with the variable lower nose isolation compression sealand isolate flowing fluids from well head control equipment.